Catheter with simultaneous brush cytology and scrape biopsy capability

ABSTRACT

A medical device performs simultaneous brush cytology and scrape biopsy on structures within an organic duct by collecting cells and tissue on a brush having irregular semi-rigid bristles, preferably formed as the hook portion of a hook and pile fastener (e.g., the hook portion of a Velcro pad). A wire guided catheter has a brush strip located near a distal end for insertion into the duct. Once the distal end and brush are positioned at a selected location within the duct, the catheter is pushed and pulled back and forth to gather cells and scrapings from the selected location, which accumulate in the irregular bristles. The catheter can be enclosed in a retractable sleeve during insertion and/or withdrawal. An enlargement at the distal end of the catheter assists in opening the duct to admit the brush. A radio-opaque marker is externally detectable to assist in locating the brush at the selected location. The relatively stiff irregular bristles improve the extent to which cells and tissues can be collected and permit collection of enough tissue to provide a biopsy sample, without substantial risk of perforation of the duct.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to devices for collecting cell samples frominternal organs, and in particular to a catheter capable ofsimultaneously performing brush cytology and scrape biopsies ofstructures within biological ducts, employing a polymeric hook pad withrelatively stiff irregularly shaped bristles for collecting cells from asample site. More particularly, a wire guided catheter having a hook padof a hook and pile fastener (e.g., Velcro) at its distal end is used forabrading against the duct walls to collect cells and tissue.

2. Description of the Prior Art

It is sometimes necessary to collect a sampling of cells from internalorgans, typically using an endoscope or laparoscope to obtain access tothe site to be sampled, for laboratory analysis in connection with adiagnosis. In connection with certain bodily ducts, a tumor in thetissue of the duct or in tissues adjacent the duct may present as anarrowing or stricture of the duct at a localized area. Cancer of thebile duct or the pancreatic ducts, for example, present as a narrowingor stricture. Similarly, strictures can be seen in the esophagus, thestomach, the colon, and other duct-like organs. It is useful inconnection with diagnosis to examine the cells at a stricture to betterassess its cause.

Known cytological techniques for collection of cell samples at ductstrictures and other sites have a number of shortcomings. The diagnosisof pancreato-biliary malignancy is an example. Normally, an endoscope isused to obtain access to the collection site, for example the pancreaticduct leading from the pancreas to the duodenum. A cell collection toolthat is basically an elongated brush usually having soft bristles set intwisted strands of wire is passed through the endoscope. Using the wireto pull the brush in opposite directions, the bristles are brushed overthe inner wall of the duct at the stricture, in an effort to displacecells from the duct wall and capture the cells in the bristles. Thistechnique is sometimes called "brush cytology" or just "cytology."

The brush can be placed in a sleeve to assist in guidance to the samplesite, to avoid picking up cells from areas other than the stricture, andto protect the sample after it is collected. The sleeve can have one ormore radio-opaque marks to help in placing the brush at the stricture.More particularly, fluoroscopy is used to visualize the location of thesleeve by the radio-opaque mark and therefore to assist in placing thebrush in the stricture.

Unfortunately, brush cytology as described is only adequate to collectsufficient cells to effect diagnosis in about 18 to 70% of attempts. Thetechnique offers no biopsy capability because it cannot effectivelyextract a gross tissue sample from the area of the stricture. Diagnosisof a potential malignancy, however, certainly requires dependableresults in the collection of cells, and may require collection of a moreextensive biopsy sample. To diagnose a malignancy associated with astricture, for example, it may be appropriate to examine the mucouslining of the duct, the tissue of the duct wall and even adjacenttissues. The known brush cannot extract sufficient cells and tissue in adependable manner. The known wire-carried brush can be reciprocatedusing the wire but it is not guided by the wire. Accordingly, the knownbrush is difficult to use effectively in difficult to reach, narrowareas of the ducts. Presently, a biopsy of the area of the stricture isobtained by passing a different instrument, typically a biopsy forceps,through the endoscope and then cutting away and removing a relativelylarge chunk of the tissue from the diseased area. However, use of biopsyforceps involves an inherent risk of perforating the duct, and for thisreason their use is not preferred.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a method and apparatus thatcan better collect a tissue sample from a stricture in a duct or fromanother anatomical structure, preferably that can obtain a sufficientsampling of cells to assist in diagnosis more dependably. Moreparticularly, there is a need to enable collection of a samplesufficient to qualify as a biopsy, but in a manner that reduces the riskof perforating the duct as compared with known techniques.

It would be advantageous therefore to provide an instrument that iscapable of obtaining a brush cytology sample that can also be used toobtain a larger tissue sample for a biopsy, preferably enablingselection of a brush sample more dependably, and enabling collection ofa gross tissue sample or biopsy, using the same tool and substantiallyvia the same procedure. Such an instrument would be particularly usefulin the diagnosis of anomalies of the pancreato-biliary structures, suchas a malignancy presented as a stricture of the ducts.

These and other objects are met according to the invention in a devicecapable of performing a brushing of tissue at a stricture in a duct forcollecting cells (cytology) and also capable of obtaining a greatersample of the tissue (biopsy) at the stricture in a procedure thatcombines cytology and biopsy. The duct can be, for example, the commonbile duct, the pancreatic duct, and any of a number of other duct-likeorgans and the like, such as, for example, the esophagus, the stomach,the large bowel, the lungs, the uterus, the ureter, the kidney, etc.,all such organs being collectively referred to herein as ducts.

The device includes an elongated, flexible catheter and a brush made ofsemi-rigid bristles with irregular shapes for capturing cells and tissuein the bristles, preferably bristles on a pad or fabric of the typeconventionally used as the hook side of hook and pile fasteners such asVelcro. The brush is located adjacent a distal end of the catheter. Thecatheter is inserted into the duct or duct-like organ, and can be passedover a guide wire for guiding the catheter into and through the duct.

According to another aspect of the invention, the bristles of the brushprovide an inherent structure for capturing and then protecting thecollected cells. Accordingly, the individual bristles can include hooks,ball-shaped, looped, mushroom-shaped or T-shaped structures at theirends, tending to collect cells and tissue and to retain the collectedmaterial during withdrawal of the device. The hooks can be separatelyformed or provided as cut loops, or formed in another manner known inconnection with use of the bristles as fastener elements.

According to another aspect, the distal end of the catheter that isinserted into the duct can be ball-tipped with a radio-opaque ball, orstructured for expanding the duct to allow the brush to pass through theduct as the bristles work on the inner wall of the duct.

The catheter can include a marking device located adjacent to the brush,such as a radio-opaque mark, to assist in guiding the catheter to adesired location in the duct, as viewed fluoroscopically. Additionally,a retractable sleeve can be provided to encompass the brush duringpassage of the catheter to a selected location in the duct, and/or toprotect the collected sample when being removed on the brush.

The invention includes a method for performing combined cytology andbiopsy in a duct using a wire-guided catheter as described. The brushnear the distal end of the catheter that is to be inserted into the ductis fabricated of semi-rigid irregularly shaped bristles, e.g., hooked orblunt ended bristles or the like, for example the bristles of a hook padmaterial such as Velcro. The method includes the steps of firstperforming endoscopy to obtain access to an opening into the respectiveduct. For example, in a bile duct or a pancreatic procedure, anendoscopic retrograde cholangio pancreatography (ERCP) is performed. Theendoscope can be brought near to the site of to be sampled, such as astricture, if this is convenient. A blunt-ended guide wire is moved intothe duct so as to pass a selected area of the duct at which the cytologyis to be performed and/or a biopsy sample taken. The distal end of thecatheter, including the brush, is then inserted over the guide wire intothe duct, i.e., with the wire passing through the lumen of the catheter.The brush bearing end of the catheter is moved to the selected area ofthe duct and pushed and pulled, back and forth over the inner wall ofthe duct. The bristles of the brush collect sample scrapings of tissueand brushings of cells at the selected area. The end of the catheterwith the brush is withdrawn from the duct through the endoscope or intoa sleeve provided to protect the sample. The scrapings of tissue andcells that cling to the brush can then be removed and analyzed bystandard methods.

According to a further aspect of the invention, the catheter can includemarkers, such as radio-opaque markers, located near the brush and forexample straddling the brush along the longitudinal axis of thecatheter, for assisting in guiding the brush to the selected area.According to another aspect of the invention, the first end of thecatheter includes an expansion mechanism for expanding the duct. Themethod includes the further step of expanding a section of the duct withthe expansion mechanism before passing the brush into the selected area.This can be especially useful in the case where the selected area has avery narrow stricture.

According to another aspect of the invention, a longitudinallyretractable sheath, or sleeve made of nylon, polyethylene, polyurethane,polytetrafluoroethylene (Teflon) or the like, covers the brush as it isguided to the selected area. The sheath is retractable in a telescopingmanner to expose the brush at the selected area before the brush ispushed and pulled over the tissues, and after brushing the sleeve can bemoved back over the brush, or the brush can be withdrawn into thesleeve. Thus the brush can be deployed internally, used and thenprotected against loss or contamination of the sample, before removingthe brush from the duct.

The catheter and the brush thereon can be withdrawn along the guidewire. After removing the catheter from the duct, a stent can be passedover the guide wire in place of the catheter, for keeping the duct openthrough the area of the stricture. The guide wire can then be withdrawn.

Cytology can be rendered more effective according to the inventionbecause a more substantial sample can be taken than with the brushapparatus conventionally known. The brush can be operated more gentlyfor collection of cells or more vigorously to obtain pieces of tissuefor biopsy analysis. Nevertheless, the brushing procedure is safer thansurgical extraction of tissue from the wall of the duct.

These and other objects of the invention will be more fully understoodfrom the following description of the invention with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial elevation view of a first embodiment of the deviceof this invention.

FIG. 2 is a partial elevation view of a second embodiment of the deviceof this invention.

FIG. 3 is a partial elevation view of a third embodiment of the deviceof this invention, including a retractable sleeve that can be positionedover the bristles of the brush.

FIG. 4a-4c are elevational views of three preferred embodiments ofbristle designs for the brush.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of a device 1 according to the invention isillustrated in FIGURE. 1. Device 1 includes a flexible, hollow tube 3,or catheter, having a ball tip 5, for example of metal. Similarstructures of the respective embodiments will be referenced by the samereference numbers throughout this specification for simplicity ofexposition. For applications such as taking simultaneous brushings andbiopsies of structures in the common bile duct and the pancreatic duct,tube 3 can be, for example, 2 m long and 0.2 cm in internal diameter,such as a No. 6 French nylon catheter, or larger or smaller, asrequired.

A blunt ended guide wire 7 is placed in the duct to be examined, suchthat the wire extends beyond the stricture or other site to be sampled.Guide wire 7 can be, for example, a 0.035 inch (0.09 cm) diameter,blunt-ended guide wire, preferably made of a resilient metal, such assteel or titanium coated with an outer layer of a material that isnonreactive, such as polytetrafluoroethylene (Teflon). A metal ball tip5 on the catheter can be provided both to push aside duct tissueswithout puncturing them and to provide a radio-opaque structure that canbe used to locate the end of the catheter, by fluoroscopy.Alternatively, the tip 5 can be a relatively wider loop end. Thecatheter is slid over the guide wire to the sampling site.

Catheter 3 comprises a brush 9, preferably arranged around the catheteradjacent the distal end, but also potentially along one lateral sideonly. Brush 9 comprises a plurality of radially extending, semi-rigidbristles 11 that protrude from a base strip that is attached adhesivelyto catheter 3 near the distal end. Individual bristles 11 have enlargedor hooked ends, which in a hook and pile fastener is a means by whichthe ends engage a pile. However, according to the invention, therelatively stiff bristles and their enlarged or hooked ends readilycollect cell and tissue samples and provide a zone radially inwardly ofthe enlarged or hooked ends where the sampled cells and tissue tend tobecome trapped.

The brush 9 can be made using the hooked side of a Velcro or other hookand pile type fastener, for example with bristles extending radiallyabout 1 to 3 mm. The length of the brush 9 along the longitudinal lengthof catheter 3 can vary depending upon the application, but preferably isat least 0.5 cm long. For most applications, it need not be more thanabout 1.5 cm in length, however, longer length brushes are also includedwithin the scope of this invention, and can be used when it is desirableto collect and perhaps to distinguish among cells and tissue collectedover a predetermined length of the duct.

Fastener pads as described generally comprise bristles formed on a baseweb of plastic or the like. The bristle ends can be formed in a numberof ways, such as by melting the ends of standing thermoplastic bristlesto provide a ball or mushroom shape or to cause the ends to bendrearwardly, forming hooks. Another technique is to form a loop pile andto cut the loops to provide a hooked bristle and a straight bristle. Allsuch alternatives produce irregular bristles useful for collecting cellsand tissue. Other forms of the grasping part of pad fastener materialscan be used as well. Preferably, the brush or bristle pad is attached bythe base of the pad to the catheter. The base can be attached byadhesive, heat welding or the like to provide a secure connection. Thebristle bearing pad can extend part way around the circumference of thecatheter, but preferably extends substantially around a full 360°.

Referring to FIG. 2, an alternative embodiment of the device includesmarkers 13, such as metal bands or clips, on one or both longitudinalsides of brush 9 for locating the distal end of the catheter and thebrush while in the duct. Markers 13 are visible by fluoroscopy. Theembodiment of FIG. 2 also includes a means for dilating the duct withlongitudinal advance of catheter 3, for assisting passage through theduct of brush 9. Brush 9 is slightly wider than the portion of catheter3 where brush 9 is mounted within the duct. The distal end of thecatheter 3 as shown has an enlarged, preferably cone-shaped structure 15in this embodiment to mechanically dilate the duct as the distal end isinserted. Other means, such as inflatable balloon catheter means, can beused as another way to dilate the duct.

Preferably, the device is used with a retractable sheath or sleeve 17,that can be moved longitudinally relative to catheter 3, in particularin both directions between a position covering the brush (as in FIG. 2)and a retracted position exposing the brush (as in FIG. 3). The sleeve17 likewise can be fabricated of nylon, polyethylene, Teflon or thelike. Sleeve 17 just fits over catheter 3, and is effective to preventbrush 9 from picking up cell or tissue samples before being deployed inplace at the sample site, and to prevent contact between brush 9 and theduct after the sample is collected, which contact could cause capturedcells and tissue to come free of brush 9 or additional cells or tissueto be picked up from other sites.

FIGS. 4a-4c illustrate different preferred embodiments for bristles 11of brush 9. In FIG. 4a bristles 11 have a ball-tip or mushroom tipstructure 19 located at the distal end of each bristle 11. Bristles 11in FIG. 4b have hooks 21 at their ends. FIG. 4c illustrates bristles 11forming closed loops 23. It is to be understood that although threespecific embodiments of bristle designs are described herein, this isnot meant to be limiting. Other bristle designs having similarcharacteristics, and in particular that have a structure effective forcapturing and holding cells and tissue, are also encompassed within thescope of the invention.

The device of this invention is used in the following manner inperforming a combination of cytology and biopsy of a stricture in apancreatic duct, for example. An ERCP is performed to gain entry to theduct. The guide wire 7 is then passed into the duct sufficiently toapproach or preferably pass a selected area of the duct at which thecytology/biopsy is to be performed. The distal end of catheter 3,including brush 9, is inserted over guide wire 7 into the duct. Theposition is monitored by viewing the ball-tip 5 or other radiographicmarker, such as clips 13, with a fluoroscope. Brush 9 is moved to theselected area of the duct. If the duct stricture is very narrow, acatheter having a mechanism for expanding the duct, such as acone-shaped end 15, can be used to dilate the duct before entry of thebrush 9 into the stricture. The brush 9 on catheter 3 is exposed byretracting the sheath or sleeve 17. Catheter 3 then is pushed andpulled, back and forth, several times such that sample scrapings oftissue and brushings of cells from the stricture cling to bristles 11 ofbrush 9, more particularly being captured by the bristle structures.Catheter 3 is then retracted into sleeve 17 (or sleeve 17 is advanced)sufficiently to protect brush 9. The catheter is withdrawn from the ducttogether with sleeve 17, through the endoscope. Guide wire 7 can bewithdrawn simultaneously or afterwards.

The scrapings of tissue and cells that cling to bristles 11 of brush 9can be removed and analyzed for abnormalities according to methods knownin the art. Prior to retracting guide wire 7, a stent or tube, alsoknown in the art, can be passed over the guide wire 7 after removal ofthe catheter 3 and left in the stricture to keep the duct unblocked.

Whereas particular embodiments of the present invention have beendescribed above for purposes of illustration, it will be appreciated bythose skilled in the art that numerous variations of the details may bemade without departing from the invention as described in the appendedclaims.

I claim:
 1. A device for collecting cells from a duct, comprising:acatheter forming a hollow tube with a brush located close to a distalend of the catheter, for insertion into the duct, wherein the brush isfabricated of semi-rigid bristles protruding radially from the tube, thebristles having irregular shaped tips whereby the cells are collected inthe bristles by scraping the brush over an inner wall of the duct; anenlargement formed in the catheter adjoining the distal end of thecatheter; wherein the enlargement occupies a position separating thebrush from the distal end, and is shaped and arranged for expanding theduct to permit passage of the brush during insertion through the ductand for expanding the duct during withdrawal to permit withdrawing fromthe duct scraped and collected cells; and, a sleeve movably disposed onthe catheter to cover and uncover the brush; wherein the sleeve isformed to be abuttable against the enlargement of the catheter forprotecting the scraped cells collected on the brush during withdrawal ofthe catheter and sleeve combination from the duct.
 2. The device ofclaim 1, wherein the bristles have hooked distal ends.
 3. The device ofclaim 2, wherein the bristles are provided on a pad of hook material ofa hook and pile fastener.
 4. The device of claim 1, wherein the brush isformed of a pad carrying the bristles and extends along the catheterlongitudinally by about 0.5 to 1.5 cm.
 5. The device of claim 4, whereinthe pad extends substantially fully around a circumference of thecatheter.
 6. The device of claim 1, further comprising at least onemarker means detectable externally of the duct, located adjacent thebrush for guiding the brush to a selected location in the duct using anexternal means for detecting the marker.
 7. The device of claim 6,wherein the marker means comprises a radio-opaque marker.
 8. The deviceof claim 6, wherein the marker means comprises a pair of radio-opaquemarkers located adjacent the brush on opposite sides.
 9. The device ofclaim 8, further comprising guide means for guiding the brush to adesired location by sliding the catheter over the guide means.
 10. Thedevice of claim 9, wherein the guide means comprises a guide wirelongitudinally extending inside the catheter and having a blunt endextending beyond the distal end of the catheter.
 11. The device of claim1, further comprises a flexible material selected from the groupconsisting of nylon, polyethylene, polyurethane andpolytetrafluoroethylene.
 12. A device for performing simultaneouscytology and obtaining a scrape biopsy of tissue and cells at astricture in a duct, comprising:a flexible hollow catheter having adistal end for insertion into the duct and capable of being fed into theduct over a guide wire extending through the catheter to pass throughthe stricture, the catheter having an enlargement terminating at thedistal end for expanding the duct; a brush having semirigid bristlesprotruding substantially radially from the catheter and formed over alongitudinal distance adjacent the enlargement, the enlargementoccupying an intermediate position between the brush and the distal end,the bristles being irregularly shaped bristles of a grasping portion ofpad fastener material, disposed substantially around a fullcircumference of the catheter; radio-opaque marker means near the brushfor locating the brush by fluoroscopy; a retractable sleeve movablebetween a covering position surrounding the brush and a retractedposition exposing the brush; wherein the sleeve is formed and arrangedto be abuttable against the enlargement of the catheter for protectingthe scraped cells collected on the brush during withdrawal of thecatheter and sleeve combination from the duct.
 13. A method forcollecting cells and tissue from a selected area within a duct,comprising:placing a guide wire in the duct such that the guide wirepasses the selected area; supplying a catheter, which catheter has adistal end, an enlargement terminating in the distal end, and a brushadjacent the enlargement, the enlargement occupying an intermediateposition between the brush and the distal end; inserting the catheterinto the duct over the guide wire, the brush with semirigid bristlesextending from the catheter, the bristles being irregularly shapedbristles of a hook portion of a hook and pile fastener, operable tocapture the cells and tissue; enlarging the duct to admit the brush bythe enlargement of the catheter at the distal end of the catheter;advancing the catheter to position the brush at the selected area;alternately pushing and pulling the brush back and forth at the selectedarea, whereupon the cells and tissue accumulate in the bristles in thewake of the enlargement when the catheter is pushed; and, withdrawingthe catheter and the brush from the duct wherein cells and tissuescollected by brush are partly pushed by the enlargement.
 14. The methodof claim 13, further comprising enclosing at least the brush of thecatheter in a sleeve at least when withdrawing the catheter and thebrush from the duct.
 15. The method of claim 13, further comprisinglocating the catheter by externally detecting at least one radio-opaquemarker on the catheter adjacent the brush during at least one of saidinserting, pushing and pulling and said withdrawing steps.